Cracking hydrocarbon oil



` Feb. 2., 1943- J. K. ROBERTS ETAL CRACKING HYDROCARBON OIL Filed July 1e', 1938 Patented Feb. 2, 1943 z,s1o,1ss casema maocaaaou on.

Joseph K. Roberts, Flossmoor, and Morris T. Carpeuter. Chicago, Ill., aslixnors to Standard Oil Company, Chicago, lll., a corporation of Indi- Appuesuon my 1s, 193s, serial No. 219,566

' (or 19e-4s) 15 Claims.

This invention relates to a combination cracking and coking process adapted for the treatment of hydrocarbon oil to produce maximum yields of gasoline or motor fuel of superior anti-knock quality. 'f Y The invention contemplates a process in which raw charging stock, such as topped or reduced crude petroleum is subjected to coking, the evolved vapors fractionated to separate a heavy condensate from lighter fractions, the heavy condensate subjected to cracking primarily to effect conversion into alarge yield of intermediate constituents adapted for subsequent conversion into gasoline, the cracked vapors subjected to frac,- tionation together with the vapors from the coking operation so as thus to accumulate,` in such lighter fractions constituents adapted for high cracking per pass cracking and iinally the cracking of such lighter -fractions in a separate cracking zone to effect conversion into high anti-knock constituents.

When it is sought to coke a cracked residue, particularly when the cracked residue is a product of a more or less drastic cracking operation,

the conversion into the coke residue is vaccomplished with a large yield of coke and a small yield-of gasoline, and such a coking operation is accompanied with a relatively large yield of gas per unit volume of gasoline or light distillate produced, as compared with the yield of gas produced in the coking of a virgin stock such as topped or reduced crude. Furthermore, the subjection of the cracked residue to coking results in the loss of constituents highly valuable for use as fuel oil. The cracked residue possesses a higher specific gravity for a given viscosity than topped or reduced crude and a consequent higher caloric value. Accordingly, in the practice of our invention,.the coking operation is applied to the virgin stock, the topped or reduced crude, to convert immediately the virgin stock to ultimate yields of volatilized products, including not only gasoline but intermediate constituents adapted for high cracking per pass conversion into gasoline, as Well as certain heavier constituents which are separately cracked to produce an additional yield of intermediate constituents. The cracked residue derived from the cracking of the intermediate constituents is segregated for the production of fuel oil. In practicing the invention the intermediate constituents are subjected to a high cracking per pass cracking operation, the resultant cracked products separated into vapors and cracked residue, and the cracked residue hash-distilled in Contact with the cracked cracking per pass cracking zone,

products produced in the cracking ofthe heavy condensate obtained in the fractionation oi' the evolved vapors from the coking operation, while lighter fractions, obtained in this fractionation from both the coking operation and from the cracking of the heavy condensate, constitute the constituents that are passed to the high cracking per pass cracking operation.

The invention further contemplates a method of processing crude petroleum to accomplish maximum yields of gasoline or motor fuel of superior anti-knock quality. In accordance with the invention the crude oil is fractionated to form a topped or reduced crude and a condensate such as gas oil. The toppedor reduced crude is subjected to coking for immediate conversion into an ultimate yield 'of volatile products andthe condensate fraction is subjected to high cracking per pass cracking for conversion into anti-knock gasoline. The products of the later cracking are separated into vapors and cracked residue and the cracked residue is passed to a flashing zone. In a preferred embodiment of the invention the topped or reduced crude is introduced into a dephlegmator receiving vapors from the coking operation and the resultant combined reiiux condensate and residual crude oil constituents are passed to the coking zone. The vapors are further fractionated to form a heavy condensate of the nature of heavy gas oil, which is subjected to cracking in a heavy gas oil cracking zone' and the resultant cracked products directed into the ash zone for separation into vapors and residue together with the cracked residue from the high cracking per pass cracking operation. In fractionating the crude petroleum, it is advantageous to fractionate the vapors into a heavy gas oil fraction and a light gas oil fraction'and the light gas oil fraction is. in accordance with the invention, directed to the high cracking per pass cracking zone, while the heavy gas oil fraction is subjected to cracking in the heavy gas oil cracking zone. In accordance with the invention, the heavy gas oil fraction from the crude oil may be refluxed in a fractionating zone in which cornbined vapors from the coking operation and the flashing operation as well as vapors from the heavy gas oil cracking operation are fractionated, heavier constituents in the vapors being collected as a heavy gas oil condensate for cycling to the heavy gas oil cracking zone and lighter fractions being combined with the light gas oil from the crude oil distillation for cracking in the high An advantageous operation in accordance with the invention is to direct lighter fractions. obtained in the fractionation of the combined vapors from. the coking operation, the flashing operation and vapors from the heavy gas oil cracking operation,

, into a fractionator in which vapors from the high conditions of low pressure approaching atmospheric, or in fact even under sub-atmospheric pressure, and preferably with the aid of a stripping medium. such as steam or gas, in order to eii'ect fractionation of extremely highboiling constituents having boiling points within the 'cracking temperature range. Inaccordance with the invention the fractionation may be so conducted as to form a condensate, having an initial boiling DO Dt o! 'upwards 0I 800 l". and.

preferably in excess of 850 F. (as determined by a vacuum distillation and interpolated to an atmospheric pressure basis), for cycling to the coking zone to be subjected to coking with the asidiaa residual constituents of-the crude petroleum.

Thus, the topped or reduced crude may be introduced into a primary dephlegmating or fractionating zone to dephlegmate the vapors from the coking zone. under such conditions `of temtillation and interpolated to an atmospheric pressure basis). By restricting the cycle stock to the ecker to material of -this extremely high boiling Point, it is found that in the complete combination process the maximum ultimate yield of gasoline is produced. Furthermore, the ratio of liquid fuel yield to the yield of coke and gas is higher when subjecting t0 the coking operation only material boiling above about 800 F. The ratio of crude residue to cycle condensate is of the order of 4:1 or 4:2. After the dephlegmation or fractionation oi' the vapors in contact with the introduced topped or reduced crude, the vapors are further fractionated to form a fraction having an initial boiling point of about 650 F.-'I00 F. and having an end point of the order of 800 F. (as determined by a vacuum distillation and interpolated to an atmospheric pressure basis). 'Ihis heavy fraction is directed to the heavy gas oil cracking zone and subjected to conversion into constituents of intermediate boiling points well adapted for treatment at high cracking per pass conditions for conversion into gasoline of high antie knock quality. Y

An important; object of our invention is to accomplish an effective cracking operation in which the oil is processed to ultimate yields with a minimum number of separate cracking operations without. however, sacrificing the yield of gasoline or the anti-knock quality thereof, or the on stream time of the unit.

For the purpose of more fully disclosing the invention reference will now be had to the accompanying drawing which is a flow diagram illustrating apparatus adapted for the practice of the invention. f

In the apparatus illustrated the charging stock such as crude petroleum is charged by a pump i0 to a heat exchanger or exchangers indicated diagrammatically' at ll, in which the charge may be preheated by heat exchange with hot products of the system. The preheated charge passes through transfer line I2 to .a heating coil I3 locatfxi in a furnace or heating chamber Il in which the charge may be heated to a desired distilling temperature. An outlet line il extends from the heating coil and is provided with branches l0 and i1. The branch il extends to a distilling and fractionating tower Il. A by-pass line Il is provided for by-passing the heating coil l! and for passing the preheated charging stock directly from heat exchanger H to the tower Il.

The tower Il is provided with suitable fractionating elements such as bubble trays and with suitable reiluxing means for accomplishing the desired fractionation therein. A steam line 2l is indicated for introducing steam into the tower to aid in stripping light ends from the tower bottoms. A plurality of trap-out trays such as 2|, 22, 23 and 2| are provided with lines 25, 2|, 21 and 2l extending from the trays, respectively. The overhead vapors pass to a condenser 2l and the distillate is collected in a receiver 3l. In practice it is advisable to pass the several condensates collected in the trays 2|, 22, 2l and 2l to side stripping towers in order to further fractionate the condensates and remove lighter constituents therefrom but for the purpose of simplicity the apparatus for stripping the several side cuts has been omitted from the drawing.

'Ihe coking unit of the process includes a heating coil 3| disposed in a suitable furnace or 'heating chamber 32 adapted to heat the oil to be coked to a temperature suiilcient to accomplish coking and a coking drum 33 into which the heating coll discharges and in which the oil is held at a coking temperature to effect coking, In practice a plurality of coking chambers are provided so that continuity of the coking operation may be maintained in conjunction with the rest of the continuous process. 'I'hus the stream from the heating coil Il may discharge into one or more of the coking chambers while in other of the coking chambers the coke may be undergoing digestion for hardening and in other of the chambers removal of the coke may be taking place and thus a substantially continuous evolution of vapors from a chamber or chambers in which coking is taking place maybe maintained. 'I'he vapors pass through a vapor line 3l to a dephlegmating tower l5. In the specific arrangement illustrated, the vapor line 24 is shown provided with branches 3i and 31 extending to the tower 35. The tower is equipped with suitable fractionating elements such as bubble trays. discs and doughnut trays or the like and witlr appropriate refluxing means for regulating thii'4 fractionation in the tower. A trap-out tray 38 is disposed beneath the branch vapor, line 30 and another trap-out tray 39 is disposed beneath the branch vapor line 31. The lower section of the tower 35 includes a separating zone 40 for separating into vapors and liquid\residue certain products as will be hereinafter explained. A drawoif line 4I is provided for removing the residue and a reflux line 42 is provided for introducing a refluxing medium to dephlegmate the vapors evolved in the separating zone Ill.

The topped or reduced crude is drawn from animos in which the condensate is heated to a cracking the crude ractionating tower i8 by a pump 43 and line di shown with one branch line 45 extending to the transfer line I2 and another branch line 45 extending to the tower 35. In one method of operation the crude `oil introduced by pump i8 is heated. by heat exchange with hot products of the system in exchanger Il, passed thence through transfer line I2 to the heating coil I3, thence lthrough line I and branch line I8 into the crude fractionating tower i8. The resultant residue is drawn from tower I3 by pump t3 and passed through lines 44 'and 4S into the tower above the trap-out tray 38. A steam line 41 is indicated for introducing steam into the trap-out tray to promote the stripping of the heavy crude residue.

In another method of operation contemplated by the invention the crude o il is heated to a moderate distilling temperature, as by heat exchange with hot products of the system in exchanger II, and the preheated oil B passed hence through the line I8 into the tower I8. The topped crude is drawn from tower I8 by pump is and passed through lines 44 and 45 to the heating coil I3 wherein the residue is further heated, after which it is discharged through line I5 into branch line I1, which communicates with line 8S through which ,the residue is discharged into the tower 35.

In either of these methods of operation oil to be coked is drawn from trap-cut tray 38 through line 48 and also, if desired, through a line 43 from trap-out tray 33, to a line and is directed by pump 5I through line 52 to the heating coil 3i.

lect with the residue in the pan 38, as well as any heavy reflux condensate collecting in pan 83, may be normally charged by the pump 5I to the heating coil 3| in which the oil is raised to a coking temperature for coking in the coking drum 33. Y

At certain times, particularly near the end o! the coking operation in a given drum 33 and immediately prior to the switching over to another of the coking drums, the vapors from the coking drum may contain more or less entrained ooky material or heavy material of a coke-forming nature, capable of causing coking difculties in the heating vcoil 3i and at such times the vapors from the coking drum, instead of entering the tower 35 through line 38 or through both lines 38 and 31, are permitted to enter the tower only through the lower line 31, and with the valve in line 49 closed, the pump 5I takes suction through line 48 on the trap-out tray 38, while the dirty material collecting in tray 38 is either permitted to overflow into the separating zone 40 or is separately withdrawn from the tower through a line not shown.

Vapors from tower 35 pass through line 53 to a fractionating tower 54 which is provided with suitable fractionating elements such as bubble trays, disc and doughnut trays or the like, and with suitable refluxing means for controlling the fractionation therein. A steam line 55 is indicated for supplying steam for stripping the reiiux condensate collecting in the lower part of the tower. Heavy reflux condensate withdrawn from trap-out tray 24 of the crude fractionating tower I8 through line 28 may be dif rected by pump 56 and line 51 into the tower 54. Reflux condensate is withdrawn from tower 54 by pump 58 and passed to a heating coil 59 positioned in furnace or heating chamber 63 Thus topped or reduced crude, togather with any reflux condensate that may coltemperature and the resultant products of cracking are passed through transfer line 8i to the separating section 40 of tower 35. The overhead vapors from tower 54 pass to a condenserAS! and the distillate is collected in e receiving drum 83.

To refer now to the apparatus for the high cracking per pass cracking operation, a pump 84 is provided with an intake line 65 manifold to the lines 25, 28 and 21, so that condensates from any or all of the trays 2l, 22 and 23 of the crude fractionating tower I8 may be withdrawn by' the pump and directed to a heating coil 88 positioned in a. furnace or heating chamber i1 adapted for applying a high cracking temperature to the oil. The cracked products pass from the cracking coil 88 into a transfer line 88, into which a quenching stock may be introduced by line- 89', and are discharged intoa separator 10 wherein separation of vapors from` liquid residue takes place. A reilux liquid may be introduced into the upper portion of separator 'I0 through a line 1I voo .tionation and the separator may be provided with suitable contacting or fractionating elements such as bubble trays, disc and doughnut trays and the like, so that the separated vapors may be given a preliminary dephlegmation before passing through a vapor line 12 to a fractionating tower 13. The tower 13 is provided with suitable fractionating elements such as bubble trays and the like, and with appropriate reuxing means for regulating the fractionation therein and accurately controlling the endpoint of the overhead fraction. The overhead vapors pass to a condenser 14 and the distillate is collected in the receiving drum or gas separator 15. Reflux condensate from the fractionating tower is cycled by pump 18 and line 11 to the heating coil 66.

Distillate from the receiving drum 83 is directed by pump 18 and line 13 to the tower '18 wherein the distillate is-subiected to fractionation, the lighter constituents passing overhead to I the condenser 14 and receiver 15 and the heavierv constituents being combined with reilux oondensate in the tower for cycling to the cracking coil 68.

'I'he separated residue collecting in the tower 10 together with any included reflux condensate resulting from the dephlegmation of the vapors therein, is withdrawn through a pressure-reducing valve 80 and directed through line 8I into the separating section 40 of the tower 35 for flash-distillation therein.

Provision may be made in accordance with the invention for withdrawing a special out or cuts from the tower 13 and for accomplishing the stripping or fractionation of the withdrawn cuts to produce a special product of desired charac teristics, such for example as a tractor fuel of relatively high flash or initial boiling point. Thus, as shown in the drawing, onor more trays such as tray 82, preferably superposed above the point of entry of the line 19, are provided, together with a line 83 for conducting the distillate to a lower pressure stripping tower 84. The tower 84 may be equipped with a steam line 85 for introducing steam and with appropriate contact or fractionating elements to insure the desired frac- The stripped distillate constituting a product of the desired ash test and boiling range is withdrawn through line 88 and the vapors from the tower are passed through a line 81 to the condenser coil 62 wherein they are subiected to condensation, together with the vapors from the tower 54.

In practicing the invention gas oil or a mixture of gas oil and naphtha is subjected to cracking in the high cracking per pass coil 68 at temperatures such as 900 F. to 1050 F., under relatively high pressures, such as 400 to 1000 pounds, under conditions of 15% to 35% cracking per pass (as measured by conversion into 400 F. endpoint gasoline); the reduced crude is heated to temperatures of about 880 F. to 925 F. in the heating coil 3| to maintain the desired coking conditions in the coking drum 33 wherein coking is carried on under relatively low pressure, such as 50 pounds or lower. and the heavy gas oil is subjected to cracking in the cracking coil 59 under temperatures, such as 900 F. to 950 F.. at pressures, such as 200 to 400 pounds. with rates of cracking per pass of about to 20%.

In an example of the invention'Mld-Continent crude is preheated by heat exchange with vaporsand condensate from tower 13 to a temperature of 625 F. and is then raised in heating coil I3 to a temperature of 740 F. The heated crude is subjected to distillation and fractionation in from the coking operation are fractionated in tower together with the flashed vapors from the high cracking per pass cracking operation as well as with' vapors from the heavy gas oil cracking operation. A temperature of '185' F. is maintained adjacent the tray 3l and with steam being introduced into the tray the reilux condensate that collects with the reduced crude for passage into the heating coil 3| consists essentially of constituents boiling above 800 F. The temperature at the bottom of the separating zone Il is maintained at about '150 F., a portion of the bottoms being passed through a cooling coil and thence back into the separating zone, while fuel oil is withdrawn through line 4l as a product of the process. Heavy gas oil oi' 800' F. endpoint from the crude stripping operation is directed through line i1 into the tower i4. Steam is introduced at the bottom of the tower and a reflux condensate is collected therein at a temperature of 650 F. The heavy gas oil having an initial boiling point or about 650 F. and an endpoint oi about 850' F. is directed to the heavy gas oil cracking coil 53 in which it is subjected to tower I8. The tower is held at l0 pounds presv sure and steam is introduced into the bottom of the tower which is maintained at a temperature of 705 F. A 200 F.-350 F. endpoint naphtha distillate is taken off overhead, a heavy naphtha cut is collected on tray 2|, a kerosene cut is collected on tray 22, light gas oil is collected on tray 23 and heavy gas oil is collected on tray 24. The fractionation is carried on with the aid of side stripping with steam to form a light gas oil of 650 F. endpoint and a heavy gas oil of about 800 F. endpoint. 'Ihe kerosene is withdrawn as a product of the process. The heavy naphtha and light gas oil cuts are combined and. after preheating by heat exchange with distillate from tower 54 and with vapors nowing from the evaporator 10, the mixture is combined with cycle condensate withdrawn from tower 13 at a temperature of 700 F. and subjected to cracking in the heating coil 68 under 150 pounds pressure with a maximum temperature of 1010 F. and with a rate of 20-25% cracking per pass. The gasoline constituents of the stock introduced into the heating coil B8 are subjected to reforming and heavier components are converted into gasoline constituents. The stream from the cracking coil is quenched to 80G-850 F. by condensate from tower 13 which is introduced to the transfer line through line 69 after being cooled as by heat eX- change with crude oil charge and water. The evaporator 10 is maintained at 200 pounds pressure and is reuxed with condensate drawn from tower 13 which after being cooled is introduced through line 1|. A top temperature of '750 F. and a bottom temperature of 810 F. is maintained in the evaporatorvlll and the evaporator bottoms are flashed in the separating zone 40 of y heated stream from coil 3| passes into the coking drum lmaintained under pounds pressure with a top temperature of 820 F. and the heated prod# The vapors ucts are converted to a coke residue.

cracking with a maximum temperature oi 950 F. under 400 pounds pressure with a cracking per pass of about 12% and the cracked products are discharged into the separating zone Il of tower I5.

. The overhead distillate from tower 54 includes light gas oil and naphtha. This distillate is withdrawn from gas separator 63 and alter being passed in heat exchange with' the vapors flowing from tower 5l to condenser 62, is reiiuxed on the tower 13 so that lighter constituents thereof may pass overhead as distillate from the tower while heavier constituents are combined with the cycle condensate passing to the cracking coil 66. The tower 13 is maintained at 200 pounds pressure with a top temperature oi 435 F. Intermediate fractions are withdrawn from tray 32 and sub- Jected to refractionation in tower 8l to produce a tractor oil which is withdrawn as a product of the process through lin'e I6 while the vapors pass through line 81 and are condensed in the condenser 82 together with the vapors from tower 54. The overhead vapors from the tower 13 are condensed in condenser 14 and collected in gas separator 15 under normal temperatures as dey sired gasoline distillate.

.carried on in the tower to produce the same character oi products as has been described in the first example, except that instead of collecting separate light gas oiland heavy gas oil cuts, only a single gas oil cut consisting essentially of light gas oil constituents is made and this gas oil is combined with the heavy naphtha cut and subjected to cracking in the heating coil 66. 'I'he crude residuum is drawn from tower i8 and directed by pump 43 through lines 44 and 45 to the otherwise carried on in a manner similar to that of the rst example,

products involving temperatures of about 800 F.

and higher, it is to be understood that the temperatures given are determined by vacuum distily lation and interpolated to an atmospheric pressure basis. v

In some cases, particularly when it is desired to withdraw relatively large portions of fractions, such as kerosene and gas oil, from the crude oil stripper as a. product or products of the process, extraneous charging stock is introduced into the system to maintain gasoline producing capacity. Thus extraneous gas oil is charged to the cracking coil 66 or is introduced into either or both of the fractionators 13 and 54.

While we have described a particular embodiment of our invention for purposes of illustration, it is to be understood that the invention is not restricted thereto and that various modiilcations and adaptations thereof may be made within the spirit of the invention.

We claim:

l. In the cracking of hydrocarbons' the process that comprises subjecting residual constituents of crude petroleum to coking temperature to effect conversion into coke residue, subjecting resultant evolved vapors to fractionation in a fractionating zone to form a heavy condensate and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a low pressure separating zone wherein separation of vapors from liquid residue takes place, passing resultant separated vapors into aforesaid fractioning zone and subjecting said vapors to fractionation therein together with vapors from the coking operation so that intermediate constituents produced in the cracking of said condensate enter into and constitute a part of aforesaid lighter fraction, subjecting oil to cracking temperature under superatmospheric pressure in a separate cracking zone under conditions of relatively high cracking per pass to eiect conversion into gasoline of high anti-knock quality, separating resultant cracked products into vapors and residue in a higher pressure separating zone', directing said liquid residue into said low pressure separating zone wherein the residue is subjected to flashing in contact with products introduced from the heavy condensate cracking zone, passing separated vapors from the higher pressure separating zone into a separate fractionating zone wherein the vapors are fractionated to form a desired distillate and higher boiling redux condensate, directing the aforesaid lighter fraction comprising intermediate constituents to the latter fractionating zone so that intermediate constituents thereof enter into and constitute a part of said reflux condensate formed therein, and directing such higher boiling reiiux condensate to `the last-named cracking zone.

2. In the cracking of hydrocarbons the process that comprises subjecting residual constituents of crude petroleum to coking temperature to eiect conversion into coke residue, subjecting resultant evolved vapors to fractionation in a fractionating zone to form a heavy condensate and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a low pressure separating zone wherein separation ci vapors from liquid residue takes place, passing resultant separated vapors into aforesaid fractionating zone and subjecting said vapors to fractionation therein together with vapors from the coking operation so that intermediate constituents produced in the cracking of said condensate enter into and constitute a part of the aforesaid lighter fraction. subjecting oil to cracking temperature under superatmospheric pressure in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline of high antiknock quality, separating resultant cracked products into vapors and residue` in a higher pressure separating zone, dephlegmating the separated vapors therein to eilect condensation of heavier constituents of the vapors, passing the dephlegmated vapors into a separate fractionating zone wherein the vapors are fractionated to form a desired distillate and a higher boiling reflux condensate, directing said liquid. residue from -the higher pressure separating zone to said low pressure separating zone wherein the residue is subjected to flashing in contact with products introduced from the heavy condensate cracking zone, directing the aforesaid lighter fraction comprising intermediate constituents to the latter fractionating zone so that intermediate constituents thereof enter into and constitute a part of said reiiux condensate formed therein, and directing such higher boiling reflux condensate to the last-named cracking zone.

3. In the cracking of hydrocarbons the process .that comprises introducing crude petroleum residue into a primary fractionating zone in contact with hot vapors therein, maintaining .such conditions of temperature and pressure therein as toleiect reflux condensation ci heavy oonstituents boiling in excess of 800 F. and form a resultant mixture of crude petroleum residue and heavy reflux condensate, introducing a stripping medium into said mixture to eiect removal of the.lower boiling components thereof and produce a stripped mixture having an initial boiling point of upwards of about 800 F., withdrawing the stripped mixture of crude petroleum residue and heavyA reiiux condensate and directing the mixture to a coking zone wherein the mixture is subjected rto a coking temperature to effect conversion into coke residue, restricting the recycling of condensate to the coking zone to said heavy fraction, passing resultant evolved vapors from the coking zone to said primary fractionating zone, passing the uncondensed vapors from the primary fractionating zone to a secondary iractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate comprising constituents boiling within a range of the order of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, introducing a stripping medium into said heavy condensate to effect removal of the lower boiling components thereof and produce a stripped condensate having an initial boiling point of the order of 650 IER-700 F., subjecting said stripped heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, withdrawing said liquid residue as a. product of the process, passing resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are' combined with aforesaid intermediate constituents from the coking operation, subjecting oil to cracking temperature in a separate cracking zone under 'conditions of relatively high cracking per pass to effect conversion into gasoline constituents of high anti-knock quality, separat- ,ing resultant cracked products into vapors and liquid residue im a separate separating zone,

passing separated vapors into a separate frac- .tionating zone wherein the vapors are subjected to fractionation to form reflux condensate and a desired-lighter distillate, directing the aforesaid lighter fraction comprising aforesaid interme-Y sultant mixture of crude petroleum residue and heavy reiiux condensate, introducing a stripping medium into said mixture to effect removal of the lower boiling components thereof and produce a stripped mixture having an initial boiling point of upwards of about 800 F.. withdrawing the stripped mixture of crude petroleum residue and heavy reflux condensate and passing the mixture through a heated passageway of restricted cross sectional area wherein it is subjected to a cracking temperature, passing the hot products from the heated passageway into an enlarged coking zone wherein the products are maintained at a coking temperature to effect conversion into coke residue, restricting the recycling of condensate tothe coking zone lto said heavy fraction, passing resultant evolved vapors from the coking zone to said primary fractionating zone, passing the uncondensed vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate comprising constituents boiling within a range of the order of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said stripped heavy condensate to cracking temsubjecting intermediate constituents so combined .to cracking temperature in a separate cracking A residue into a primary fractionating zone in contact with hot vapors therein, withdrawing a reperature to eiiect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, passing resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed'in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation,

sultant mixture of crude petroleum residue and heavy condensed constituents and directing .the mixture to a coking zone wherein the mixture is subjected to a coking temperature to effect conversion into coke residue, passing resultant evolved vapors to said primary fractionating zone, passing vapors from 4the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation to form a heavy condensate and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher c boiling than gasoline, directing resultant cracked products into a low pressure separating zone wherein separation of vapors from liquid residue takes place, passing resultant separated vapors to said primary fractionating zone so that said `vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from .the coking operation, subjecting oil to cracking\ temperature under superatmospheric pressure in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline of high anti-knock quality, separating resultant cracked products into vapors and residue in a higher pressure separating zone, directing said liquid residue into said low pressure separating zone wherein the residue is subjected to flashing in contact with products introduced from the heavy condensate cracking zone, withdrawing a liquid residue from the low pressure' separating zone as a product of the process, passing separated vapors from the higher pressure separating zone into a separate fractionating zone wherein the vapors are fractionated to form a desired distillate and higher boiling reux condensate, directing .the aforesaid lighter fraction comprising intermediate constituents to the latter fractionating zone so that intermediate constituents .thereof enter into and constitute a part of said reflux condensate formed therein, and directing such higher boiling reflux condensate to the last-named cracking zone.

6. In the cracking of hydrocarbons the process that comprises introducing crude petroleum residue into a primary fractionating zone in contact with hot vapors therein, maintaining such conditions of temperature and pressure therein as to effect condensation of a heavy fraction consisting essentially o f constituents boiling in excess of 800 F., withdrawing the resultant mixture of crude petroleum residue and condensed heavy fractionand directing the mixture to a coking zone wherein the mixture is subjected to a coking temperature to eiect conversion into coke residue, restricting the recycling of condensate to the coking zone to said heavy fraction, passing resultant evolved vapors from the coking zone to said primary fractionating zone, passing the uncondensed vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are. subjected to fractionation to form a heavy condensate having an initial boiling point of about 650 F.700 F. and an end pointof about 800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to eifect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, withdrawing said liquid residue as a product of the process, passing `resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones andintermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting oil to cracking temperature in a separate cracking zone under conditions of relatively high cracking per pass .to effect conversion into gasoline constituents of high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone,

p-assing separated vapors into a separate fractionating zone wherein the vapors are subjected to fractionation to form reflux condensate and a desired lighter distillate, directing the aforesaid lighter fraction comprising aforesaid intermediate constituents into the latter'fractionating zone so that such intermediate constituents are combined with reflux condensate therein and directing said reflux condensate to the lastnamed cracking zone.

7. In the cracking of hydrocarbons .the process that comprises introducing crude petroleum residue into a primary fractionating zone in contact with hot vapors therein, maintaining such conditions of temperature and pressure therein as to .effect condensation of a heavy fraction consisting essentially of constituents boiling in excess of 800 F., withdrawing the resultant mixture of crude petroleum residue and condensed heavy fraction and directing the mixture to a coking zone wherein the mixture is subjected to a coking temperature to effect conversion into coke residue, restricting the recycling of condensate' to the coking zone to said heavy fraction, passing resultant evolved vapors from the coking zone to said primary fractionating zone, passing the uncondensed vapors from the primary fracticnating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate consisting essentially of constituents boiling within the range of 650 lit-800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue 'takes place, withdrawing said liquid residue as a product of the process, passing resultant separated -vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid inter- 1 mediate constituents from the coking operation, subjecting oil to cracking temperature in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline constituents of high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, passing separated vapors into a separate fractionating zone wherein the vapors are subjected to fractionrtion to form reflux condensate and a desired lighter distillate, directing the aforesaid lighter fraction comprising aforesaid intermediate constituents into the latter fractionating zone so that such intermediate constituents are combined with reux condensate therein and directing said reux condensate to the lastnamed cracking zone.

8. In the cracking of hydrocarbons the process that comprises subjecting Aresidual constituents of crude petroleum to coking temperature to effect conversion into coke residue, passing resultant evolved vapors to a primary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to effect condensation of `a heavy fraction consisting essentially of constituents boiling in excess of 800 F., cycling said heavy fraction to the coking zone' wherein it is heated at a cracking temperature and subjected to cracking and coking with said residual constituents of the crude petroleum, restricting the recycling` of condensate to the coking zone to said'heavy fraction, passing the uncondensed vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate consisting essentially of constituents boiling within the range of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher 'boiling than gasoline, subjecting said heavy condensate to cracking temperature to eiect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process,

passing resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting intermediate constituents so combined to cracking temperature in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline constituents of .high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, and passing the separated vapors into a separate fractionating zone wherein the vapors areusubjected to fractionation to recover a desiredv gasoline product.

to a coking temperature to eiect conversion into coke residue, restricting the recycling of condensate to .the coking zone to said heavy fraction, passing resultant evolved vapors from the coking zone to said primary iractionating zone, passing the uncondensed vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate consisting essentially of constituents boilingl within the range of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline. subjecting said heavier condensate to cracking temperature to eiect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, preventing the return of any of said liquid residue-to the coking zone and withdrawing said liquid residue as a product of the process, passing resultant separated vapors to said primary fractionating zone so that said vapors are iractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting intermediate constituents so combined to cracking temperature in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline constituents of high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, preventing the return-of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, and passing the separated vapors into a separate fractionating zone wherein the vapors are subjected to fractionation to recover a desired gasoline product.

10. In the cracking of hydrocarbons the process that comprises introducing crude petroleum residue into a primary fractionating zone in contact with hot vapors therein, maintaining such conditions of temperature and pressure therein as to eiect condensation of a heavy fraction consisting essentially of constituents boiling in excess of 800 F., withdrawing the resultant mixture of crude petroleum residue and condensed heavy fraction and directing the mixture .to a coking zone wherein the mixture is subjected to a coking temperature to eiect conversion into coke residue, restricting the recycling of condensate to the coking zone to said heavy fraction, passing resultant evolved vapors from the coking zone to said primary fractionating zone, passing the uncondensed vapors from the primary fractionating zone to a secondary fractionatng zone whe-rein the vapors are subjected to fractionation to form a heavy condensate having an initial boiling point of about 650 F.-700 F. and an end point of about 800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking .temperature to eil'ect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation or vapors from liquid residue takes place, preventing the return oi any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, passing resultant separated vapors to said primary fractionating zone so that said vapors are iractionated in the primary and secondary iractionating zones and intermediate constituents formed in the cracking ot said heavy condensato are combined with aforesaid intermediate constituents from the coking operation. subjecting intermediate constituents so combined .to cracking temperature in a separate cracking zone under conditions oi relatively high cracking per pass to eiect conversioninto gasoline constituents oi high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, and passing the separated vapors into a separate Iractionating zone wherein the vapors are subjected to iractionation to recover a desired gasoline product.

l1. In the cracking of hydrocarbons the process that comprises subjecting crude petroleum to fractionation to form a crude residue, a high boiling condensate having an end point of the order of 800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, introducing said crude residue into a vprimary fractionating zone in contact with hot vapors therein, maintaining such conditions oi temperature and pressure therein as to effect condensation of a heavy fraction having an initial boiling point of the order of 800 F.-850 F., withdrawing the resultant mixture of crude petroleum residue and condensed heavy fraction and directing the mixture to a coking zone wherein the mixture is subjected .to a coking temperature to eiect conversion into coke residue, passing resultant evolved vapors to said primary fractionating zone, passing vapors from the primary fractionating zone to a secondary fractlonating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate consisting essentially oi constituents boiling Within the range of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, introducing said high boiling condensate from the crude fractionation to said secondary fractionating zone, subjecting said highboiling condensate to cracking temperature to eilect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid` residue takes place, withdrawing said liquid residue as a product of the process, passing resultant separated vapors to said primary iractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents froxn the coking operation, subjecting intermediate constituents so combined and intermediate constituents obtained lOJSS a coking zone wherein the mixture is subjected from the crude petroleum lfractionation to cracking temperature under conditions of higher cracking per pass than obtain in the cracking oi' the aforesaid heavy condensate to effect conversion into gasoline constituents of high anti-knock quality, and separately fractionating the resultant cracked products to recover a desired gasoline product.

12. In the cracking of hydrocarbons the process that comprises heating crude petroleum and separating it into vapors and residue, subjecting the vapors to fractionation to form a fraction comprising intermediate constituents higher boiling than gasoline, introducing said crude residue into a primary iractionating zone in contact with hot vapors therein, maintaining such conditions of temperature and pressure therein as to effect cohdensation of a heavy fraction consisting essen'- tially of constituents boiling in excess of 800 F., withdrawing the resultant mixture of crude petroleum residue and condensedheavy iraction and directing .the mixture to a coking zone wherein the mixture is subjected to a coking temperature to effect conversion into coke residue, passing resultant evolved vapors to said primary fractionating zone, passing vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to form a heavy condensate consisting essentially of constituents boiling within the range of 650 F.800 F. and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, passing resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractlonating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting intermediate constituents so combined and intermediate constituents obtained from the crude petroleum fractionation to cracking temperature under conditions of higher cracking per pass than obtain in .the cracking of the aforesaid heavy condensate to effect conversion into gasoline constituents of high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, preventing the return of any of said liquid residue to the coking zone and withdrawing said liquid residue as a product of the process, and passing the separated vapors into a separate fractionating zone wherein the vapors are subjected to fractionation to recover a desired gasoline product.

13. In the cracking of hydrocarbons the process that comprises heating crude petroleum and separating it into vapors and residue, subjecting the vapors to fractionation to form a fraction comprising intermediate constituents higher boiling than gasoline, introducing said crude residue into a primary fractionating zone in contact with hot vapors therein, withdrawing a resultant mixture of crude petroleum residue and heavy condensed constituents and directing the mixture to to a coking temperature to effect conversion into coke residue, passing resultant evolved vapors to said primary fractionating zone, passing vapors from .the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation to form a heavy condensate and a lighter fraction comprising intermediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking .temperature to effect conversion into intermediate constituents higher boiling than gasoline. directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, with- -drawing said liquid residue as a product of the process, passing resultant separated vapors to said primary fractionating zone so' that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking of said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting aforesaid fraction comprising intermediate constituents higher boiling than gasoline obtained from the crude petroleum-to cracking temperature in a separate cracking zone under conditions of relatively high cracking per pass to effect conversion into gasoline constituents of high anti-knock quality, separating resultant cracked products into vapors and liquid residue in a separate separating zone, passing separated vapors into a separate fractionating zone wherein the vapors are subjected to fractionation to form reflux condensate and a desired lighter distillate, directing the aforesaid lighter fraction comprising aforesaid intermediate constituents into the latter fractionating zone so that such intermediate constituents are combined with reilux condensate therein and directing said reiiux condensate to the last-named cracking zone.

14. In the cracking of hydrocarbons the process that comprises heating crude petroleum and separating it into vapors and residue, subjecting the vapors to fractionation to form a fraction comprising intermediate constituents higher` boiling than gasoline, introducing said crude residue into a primary fractionating zone in contact with hot vapors therein, withdrawing a resultant mixture of crude petroleum residue and heavy condensed constituents and directing the mixture to a coking zone wherein the mixture is subjected to a coking temperature to effect conversion into coke residue, passing resultant evolved vapors to said primary fractionating zone, passing vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation to form a heavy condensate and a lighter fraction comprising intermediate constituents higher boil:- ing than gasoline, subjecting said heavy condensate to cracking temperature to effect conversion into intermediate constituents higher boiling than gasoline, directing resultant cracked prod- -ucts into a low pressure separating zone wherein separation of vapors from liquid residue takes place, passing resultant separated vapors to said primary fractionating zone so that said vapors are fractionated in the primary and secondary fractionating zones and intermediate constituents formed in the cracking oi said heavy condensate are combined with aforesaid intermediate constituents from the coking operation, subjecting aforesaid fraction comprising intermediate constituents higher boiling than gasoline obtained from the crude petroleum to cracking temperature in a separate cracking zone .under conditions of relatively high cracking per pass to effect conversion into gasoline constituents of high Vanti-knock quality, separating resultant cracked products into vapors and residue in a higher pressure separating zone, directing said liquid residue into said low pressure separating zone wherein the residue is subjected to ashing in contact with products introduced from the heavy condensate cracking zone, passing separated vapors from the higher pressure separating zone into a. separate fractionating zone wherein the vapors are fractionated to form a desired distillate and higher boiling reiux condensate, directing the aforesaid lighter fraction comprising intermediate constituents to the latter fractionating zone so that intermediate constituents thereof enter into and constitute a part of said reux condensate formed therein, and directing such higher boiling reux condensate to the lastnamed cracking zone.

15. In'the cracking of hydrocarbons the process that comprises separately distilling crude petroleum to separate residual constituents from intermediate constituents higher boiling than gasoline, subjecting such residual constituents to coking temperature to effect conversion into coke residue, passing resultant evolved vapors to a primary fractionating zone wherein the vapors are subjected to fractionation under such conditions oi' temperature and pressure as to effect condensation of a heavy fraction consisting essentially of constituents boiling in excess of 800 F.. cycling said heavy fraction to the coking zone wherein it is heated at a cracking temperature and subjected to cracking and coking with said residual constituents ot the crude petroleum, restrict-.inar the recycling of condensate to the cokline product.v .c

ing zone to said heavy fraction, passing vapors from the primary fractionating zone to a secondary fractionating zone wherein the vapors are subjected to fractionation under such conditions of temperature and pressure as to separate a heavy condensate consisting essentially of constituents boiling within the range of 650' F.800 F. from a lighter fraction comprising inter mediate constituents higher boiling than gasoline, subjecting said heavy condensate to cracking conditions o1' temperature and pressure to eiectconversion into intermediate constituents higher boiling than gasoline. directing resultant cracked products into a separating zone wherein separation of vapors from liquid residue takes place, combining resultant separated vapors with vapors from the coking operation for fractionation therewith so that intermediate constituents produced in the cracking of said condensate are combined with intermediate constituents from the coking operation, subjecting intermediate constituents so combined and intermediate constituents obtained from the crude petroleum distillation to cracking temperature under conditions of higher cracking per pass than obtain 1n the cracking of the aforesaid heavy condensato to effect conversion into gasoline constituents 0i high anti-knock quality, directing the resultant cracked products into a second separating zone wherein separation of vapors from liquid residue takes place, withdrawing said liquid residue to segregate it for the production of fuel oil. and passing separated vapors from said separating zone to a second fractionating zone wherein the vapors are fractionated to recover a desired gaso- JOSEPH K. ROBERTS. MORRIS T. CARPENTER. 

